Method of and apparatus for making pipes and conduits of clayware



Filed June 1o. 1947 Aug. 3o, 1949. J F BOOTH l 2,480,442

METHOD OF AND APPARATUS FOR MAKING PIPES AND CONDUITS OF CLAYWARE l 5 Shee'ts-Sheet l A t torn @y Aug. 3.o,v 1949.

Filled June 10, 1947 fm1-ILL J. F. BOOTH METHOD OF AND APPARATUS FOR MAKING PIPES AND CONDUITS OF CLAYWARE Afton/yay 5 Sheets-Sheet 2 Aug- 30, 1949. J. F. BOOTH 2,480,442

METHOD OF AND APPARATUS FOR MAKING PIPES AND CONDUITS OF CLAYWARE Filed June 10,v 1947 s sheets-sheet s el," e4 se.

Attorney Patented Aug. 30, 1949 ME'rHoD 0F AND APPARATUS FOR MAKING PIPEs AND coNDUrrS oF CLAYWARE John F. Booth, Hazlehead, near Sheffield,V England Application June 10, 1947, Serial No. 753,690

In Great Britain .lune 18, 1946 1 This invention relates to the moulding of pipes, conduits, and similar articles of clayware in moulding pressesand is particularly directed to reducing the manual control ordinarily found necessary with such presses.

In the manufacture of socketed articles, it is usual for the clay to be extruded downwardly into a mould containing a core (or a number of cores) land then to be forced from the mould whilst supported on a table that remains locked against the end of the mould until formation of the socket is completed and is then lowered. Release of the table and cutting-off of the extruded article to approximately its required length are performed manually by an attendant. Lowering of the table enables each article in turn to be removed from the press for nishing operations.

According to the present invention, there is provided a moulding press for forming pipes, conduits, or like articles from clay, wherein a fringe of clay is allowed to exude between the end of a mould and the face of a supporting table for the time being locked against the end of the mould as evidence of the completion of a mouldingoperation of the press, and wherein means responsive to the exudation of said fringe are provided for effecting Yrelease of the table, thus allowing the moulded article to be extruded from the mould without manual control. Preferably, the severance of the article to approximate length by a cut-off wire or the like is automatically effected by the movement of the table at or near the end of its movement.

The fringe preferably contacts a switch (which should preferably operate in a low-voltage Ycircuit) serving to energize a relay powerful enough to actuate one or more devices, ejg., electric,

pneumatic, hydraulic, or mechanical devices, or combinations thereof, which effect release of the table.

According to a further feature of the invention, the table is lowered below the position it reaches when the full length of the article has been extruded, to permit the article to beftransferred from the press. For this purpose, a head on the lower end of a centre rod or other extension car- /ried by the table (which head co-operates with the table-locking device when the table is pressed against'the end of the mould) is seized by a grabbing device and pulled downwards. This grabbing device then thrusts the table upwards into locking position, releasing itself from the head and allowing the locking device to re-engage.

The transfer of the pipe may be effected manually, but preferably a transfer mechanism is 20 Claims.

used, e. g., of the `type'described in U. S. Patent Application Serial No. 753,691, filed on even date herewith, to reduce manual attention. In such a case, the operation Vof the 'transfer mechanism is co-ordinated with the movements of the press mechanism initiated by the production of the fringe. The finishing operations are also preferably elected automatically, e. g., by a machine as described in U. S. Patent Application Serial No. '753,692,`1iled on even date herewith, and again coordination between the operation of the press and the finishing machine may be provided for by permitting the fringe to bring about actuation of the nishing machine.l M Y In`addition to controllingV the cut-ofi device, the table movement is conveniently used tocontrol various other operations, such as starting and stopping of the screw or other extrusion device, e. g., by means of a clutch or valve, operation of the grabbingdevice, and re-engagement of the table-locking device. Again, a nozzle carried by the table may be connected to an oil-pipe to spray the moulding faces as the table approaches the end of the mould.

The invention is particularly suited to the production of a socketed pipe or conduit, the table co-operating with the base of the mould to shape the socket portion, while the pipe portion is extruded during the lowering of the table. Multiple conduits may be produced by theV usev of a multiple mould vand. an appropriately shaped table.

The invention will now be described infgreater detail with reference to the accompanying drawings, which are largely diagrammatic, as applied to the manufacture of socketed pipes suitable for use as conduits. i Y

In the drawings: f

Figure 1 is a part-sectional elevation of a moulding press constructed according to the invention.

Figures 2 and 3 are views similar to Figure y1, showing the various parts of the apparatus in different positions during the formation of a pipe,

Figures 4 and 5 are an elevation and plan, respectively, of part of the apparatus shown in Fgure '1, drawn to a larger scale, and

Figures 6, 7 and 8 are diagrams illustrating the transfer of the pipes from the press to a finishing machine. f Y j Referringto Figures v1 to 3, the press is driven by a suitable sourceof power through a belt pulley Il freely mounted onv a driving shaft I2 housed in suitable bearings I3 vin the main framework Ii pf the'machine, The pulley II is provided with a clutch plate I6 co-operating with a toggle-operated clutch, generally indicated by reference numeral I1, slidably mounted on the shaft I2 and driven by a feather key I8, the clutch being operable by a clutch lever I9, pivoted at 2| on the framework I4, through toggle linkage generally indicated ,'by rreerence mun-retail 22. Secured to =the'driving `shaft I2 is afbevel pinion 23 arranged in engagement with a bevel wheel 24 secured to a vertical shaft 26 rotatably mounted in suitable bearings in a feed -chamber 42.1 .surmounting a mould chamber 28. -feedfc'hamber is provided with an inlet chamber (not shown) through which the clay 29 is fedfat frequ'iredintervals. The mould chamber 28 depends from a wall member 30 forming part ofthe eframework I4 and spanning a pair of pillars 3| and :321securedto a base plate 33 at floor level. The clay 29 is fed downwardly in the feed chamber 21 by inclined blades 34 attached to the shaft 26, the blades `feeding the lclay'il tto :a continuous rwomn f3.6 secured "to =theshaft 25 `tinfthe flower :part fnfdreifeed chamber. The mormexn'udes the :clayZ-B into the mould chamber 328 through .suitable :apertures in lth'e wall member 38.

Dependingrom the wall imem'ber 3"risa:.cen tral core `31 which entends through .a central opening in the ibase T38 :of VSftl'ie Smould chamber leaving 'an annular :extrusion throat L39. *Slidably mounted ion fstuds lil `.formed *with heads .42 is Lan annular die 'R8 fbhe insidefsurfa'ce .of .which is shaped fto conform tothe fouter :surface .fof `:the socketl portion Afof the pipe. die 543 :is fheld in position against ftheilolvver face :of the ibase 38, during the mouldingpperatron, .bythe riiange 44 of -a flanged Aannular'core 'memberifl the fouter surface of which iis shaped to :conform :to 'the inner-surface fo`f the .socket portion sof the p'ipe. The :flange 144 "is dnotched 'at :intervals Eto form passages L41 :giving :access vto the fannular espace between the Jcore member :'46 sand the die :43 :so 'as to Vvpermit a Jifringefil11i-clayitoxexudebetween the upper face of fthe diange andithe lower :face of the die 43 during the fomationnfithe-rsocket portion of Ithe pipe.

The `core member 4651s secured to a table 249 slid'ably mounted von `Vthe fpiillars 13.1 Vand 232 wand provided 'with counterweights SiI attached :to 'chains 52 passing Lover pulleys 53, 'the :other .sends of the chains lbeing -gsecured to brackets 54 lat tached to fthelftabe jThe ltbleliis provided with a central shaft 56 which passes through :a bearing :'51 fthe ibase Aplate 333 and-extends Ainto 'a lpit 15B 'beloW-fio'orlevl. The -fshaft' is for-med near Avits 'extremityfwthz-a-*reducedfpontionfi :and i terminates in Vall'lea'd 181. 'Hille-table .'49 is locked in the moulding position by a lockingdevicefconsisting of a pair of frames BZbetween-wvhich is `pivotally 4mountedfat 253 a rcylinderm containing an air piston vpivotally roonn'ected at 26:'1 .-"to Ja pair of toggle links 68 provided with pins'G'9.:arranged to l-ri'de iin fcurve'dslots "1?I 2in .the Iframes 452, the iupper flirikbeing fprovidedwvith allocking pad 12 'which bears against fthe T'head '6| :of the shaft A136 when the 'able iis in flocked position.

Arranged below the Tlcic'ling "idevlice the fpit 58 is a, grabbing device Iconsisting xo'f 1a :pair Iof hook members 118 fp'ivc'tally i attached to 'a 'crosshead?! 4 and *provided =with fpins fl'iarranged to bear in cam slots 11 in a pair of frames i158 se- -cured inthe pit 8. 'The Aci-'osshead -T4is Lattached to an =air piston "'19 arranged tojslide in -a cylinder 8| lattached to 4"the iframes E18. "The hook members "T3 are A'causedTby 'fthe -s`lots` TTI, lduring 'the -downward `'strke of -ft'heffpiston 19,

.4 firstly to move towards each other for the purpose of engaging the head 6| of the shaft 58 when the table is at the limit of its movement under extrusion as described below, and then to remain in engagement with the head 6| during the downward stroke of the piston 19 so as to give tlie'table '49 tan additional Adownward movement for the purpose of removing the extruded pipe as described below.

In Figure 1, the various parts of the press are shown yin `the positions that they assume just .ia-iter Vthe commencement of an extrusion cycle, the table 49 being for the time being locked against -the base-fof the moulding chamber by the iocking device. A complete cycle of operations of .the press `willnow be described together with fthe construction and operation of various mechanisms not previously described, as they perform Atheir-functions.

The clay is extruded into the mould chamber 28 Iby the informi-3B, the clutch I1 .beingiengaged andthe shaft `26 rotating. As the Vclay A'moves downwardlyin they mould chamber, itis extruded through the annular throat v39 and fiirstlls iup the annular space between the fcore member '4B and the annular die 43 so asito .form '.the ,socket portion 182 'of the pipe. As soonias the l'annular space is lled and the Asocket portion thus completed, further extrusion pressure causes clay to exude from the .passages 441 :in the 'anger44 -to form the lfringeA, extrusion continuing until aportion of the fringe :48 strikes Ja spring-loaded switch member S83 attached fto a bracket :94 'depending from thebase ofthe mould chamber. The amount of fringe allowed to be extruded :is controlled by the v.position :of the switch member 83 which can be .adjustedby V-means of a slotfin the bracket 584. 'The lswitch is wired in .a .low voltage circuit, :and operates a second .switch-B6 vin a high voltage circuit, itheiswitch T86, in turn, operating a solenoid 81. 'The circuits are shown diagrammatically in Figure :1.

The vsolenoid 81 is pivotally :attached to 'one arm '88 o'f a tWo-armedlever 88, 891the arm 88 being also pivotally :attached to the stern I9| :of an air valve 92 controlling the piston 66 -of 'the locking device through circuits 93 and '94,.compressed air at 'a `pressure of about 100 lbs. -per Asquare inch being 'fed tothe -valve '92 through a pressure line'96. `The Aother armf89 of the'twolarmed lever 88, 89 is caused, upon operation of the solenoid 81 to move into va position `in the downward path of a roller 91 carried'byian rarm v98 pivotally mounted at 99 -on the upper surface 4of the table '49 so as to be freely pivotable in an Vupward direction but prevented from pivotal movement ina downward .direction by the upper surface of the table.

InlFigure 1, the switch memberiiv has just been operated by the fringe 48 and the solenoidzBI has moved the lever88, 89 to operate the valve 92 .to-disengage the locking device from the shaft -56, thus leaving the table `49 'free to move downwardly. As soon as the table is released, it is `forced downwardly 4by the clay extruding `'from the throat 39, such motion causing the formation `of the body portionllll of thepipe as shown'in Figure 2, the socket `portion`82 descending with the core member '46. Thetable 49 continues its `downward movement .under the extrusion presfsure until ra roller |02 mounted on the table49 'strikes a roller '|03 `carried .by a valve-operating arm |04 pivotally mounted in a -bracket- |506 `extending from an upright I 81 forming'partof the general '.frameworkl'4. The` valve-:operatingarm |04 is connected by a pivoted link |08 to a similar arm |09 pivotally mounted on a valve chest ||0 .and carrying a roller the arm |09 being connected to valve members 2 and H3. The valve chest 0 is connected by conduits ||4 and ||6 to an air cylinder ||1 pivotally mounted on the framework |4 and containing a piston IIS pivotally attached tothe clutch-operating lever I9, the valve chest being fed by the main pressure conduit 96. The arm |04 is movedby the roller |02 through a considerable arc in operating the valve members ||2 and ||3 so as to be clear of the roller l|02 on the return stroke of the table 49, and at the same time to move the arm |09 Yto such a position that its roller lies in the Apath of the roller |02V on the upward stroke of the table 49.

As mentioned above, the table'49- continues its downward movement until the roller |02 strikes the roller I 03 whereupon compressed air is caused to flow through the conduit ||4 and causes the Vpiston ||8 to move to the right (as viewed in Figure 1) and pivot the lever I9 in the direction of release, thus disengaging the clutch I1 and stopping the extrusion process. The table 49 is thus brought to rest. As the table approaches the limit of its extrusion movement, a roller ||9 engages the adjacent one of four projections |2| of a star wheel |22' arranged inthe path of the roller ||9 and causes it to rotate through a quarter of a revolution to operate a rotary valve |23 through which air from the main pressure line 96 is supplied to an air cylinder |24 through conduits |26 or |21, the `cylinder' |24 being pivotally attached to a bracket |23 extending from the upright |01. A piston |29 arranged in the cylinder |24 is connected to a cutter bow |3| pivotally mounted on the pillar 3| and containing a' cutting wire |32 movable within the zone bounded the studs 4|. As the rotary valve |23 is operated, therefore, compressed air is supplied to the cylinder |24 and the cutter bow is caused to swing so that the cutting wire |32 passes through the extruded pipe at a position between the lower face of the base 38 of the mould and the upper face of the die 43, the die 43 having dropped on to the heads 42 of its supporting studs 4| upon commencement of the downward movement of the table 49, the droppingof the die 43 being assisted by weak springs |33 embracing the studs 4| between the die and the base' 38. The roller I9 is carried in an arm |34 pivotally mounted on the side of the table 49 so as to be freely pivot--V able in a downwarddirection but prevented from pivoting in an upward direction by a stop, the arm |34 being held in its horizontal position by a spring.

Substantially simultaneously with the operation of the rotary valve |23 by the roller ||9, a roller |36 mounted in an arm |31 on the table 49 in a manner similar to that of the rollers 91 and ||9, being allowed to swivel downwardly from the horizontal but not upwardly, is caused to strike a valve-operating slipper v|38 pivotally mounted on an upright |39 forming part of the framework I4. The slipper |38 is arranged in engagement with the stem |4| of an air valve I 42 connected to theV grabber cylinder 8| by conduits |43 and 44 and supplied with compressed air from the main pressure line 96, the stem being spring-urged outwardly so as to urge the slipper into the path of movement of the roller |36, a stop being provided on the slipper to limit the action of the spring. Upon engagement of the slipper |38 by the roller |36, compressed air is fed by the conduit |43 to the upper end of the cylinder 8| and the piston 19 is caused to move downwardly, thus causing the hook members 13 to move inwardly to grab the head 5| of the shaft 56. The table 49 thus comes to rest momentarily at the limit of its extrusion movement, the completed pipe being severed by the wire |32 during the rest period. The position of the various parts 'of the apparatus during the rest period isindicated in Figure 2, the completed pipe having been severed and the hook members 13 being aboutV to grab the head 6| of the shaft 56.

Continued downward movement of the piston 19 of the grabbing device causes the hook members 13 to drag the table 49 further down to the position shown in Figure 3, in which position, the completed pipe is clear of the die 43 and can be removed from the table. During this movement, the roller |36 moves clear of the slipper |38 and thus allows the slipper to spring outwardly, such action reversing the valve and causing the piston 19 to rise, and whilst the valve is reversed substantially simultaneously with the table 49 reaching its lowermost position under the action of the grabbing device, the table does not start to rise immediately because of the length of the reduced portion 59 of the shaft 55, the hook members 13 moving idly over the reduced portion. The table 49 thus has a denite dwell at its lowermost position, the duration of the dwell being determined by the length of the reduced portion 59 of the shaft 56. The completed pipe is removed from the table during the dwell by a transfer mechanism referred to below.

The action of the grabbing device on the up= ward stroke of the piston 19 is to thrust the table upwardly, assisted by the action of the counter weights 5|, the hook members being thrown. clear of the shaft 55 towards the top of the stroke by the action of the cam slots 11, and the table continues its upward motion under its own momentum. During the upward movement, the rollers |35 and |I9 drag downwardly against the slipper |38 and star wheel |22, respectively, and thus have no operative action. As the table approaches the mould chamber, a roller |45 having a positive action only in the upward direction .strikes a pair of valves |41 and |43 in succession, the valve |41 operating an oil injector |49 so as to deliver a small quantity of oil into a spray nozzle |5I through a conduit |52 while the valve |48 is an air valve and passes compressed air through a conduit |53 to the nozzle |5| and thus causes the oil to issue from the nozzle in the form of a spray which is directed on to themoulding surfaces of the core member 46 and the dieV 43. f

As the table 49 is about to reach the base of the mould chamber, the roller 91 strikes the arm 89 of the two-armed lever 89, 99 and causes it to reverse the valve 92, thus once more bringing into operation the locking device which rams the table upwardly against the base of the mould chamber, 4the iiange 44 of the core member d5 causing the die 43 to be moved upwardly on its studs 4| and nipped between the ange 94 and the base 38. Substantially simultaneously with the action of the roller 91, the roller |92 strikes the roller lil on the arm |39 and causes the valve members I2 and H3 to reverse and operate the piston H3 to engage the clutch I'. Extrusion of the clay 2S now starts once more and the Vcycle .of'operations is repeated. Y n

The completed pipes are removed from the table in succession by a combined transfer and nish- .ing mechanism similar to that described -in- U. S.

12noon@ :Patent Application, Serial Nos; 753,691 and 153,692; reference beingmade tothose specificadi'onsiorffull'detailsiof 'the transfer and finishing ioperations. The -transierring operation is indi- `cated-diagramrnati'callyin Figures 6, 7 and 8, the .transfer being eiectedi vby Yone of Va series of saddles [EI-.each having; a. permeable surface i512 to which suction zapplied at the moment a .saddle `IS lfreachesfthejipipeon the tablets. The transferringmovementfcfthe-saddles i'G-l is initiated by'the'table e9 :as it approaches the limit oi its extrusion movement, a roller 'H53 'having a fpositlve movement the downward direction only, engaging. a-slipper -ISA movement of which operates :a spring-loaded valve IES controlling the suppllyfofcompressed air -to fa cylinder l which eiects reciprocaftion -of `the saddle-supporting trame 4:68 inaslide member l-il. As the table approaches itlfle-limitnof its movement under the Vactionioi .thegrabbingdevica the roller i633 moves clear 'of the slipper 454 so that the valve IES springs baci; into-reverse position and 'causes retractionof- :the saddle-supporting frame its dur- -ing 4the -d-rwell of the vtable 43 in its lowermost position.

The saddles lilly intl-iisexample are mounted Aon a rotatable member l'I-I, land in addition to their transferring function, they serve the -purposeof .supporting the pipes during finishing operations. .The rotatable member l'l operates intermittently, and its movements are controlled by a Isolenoid wired `in tbe'circuit controlled by -thefringeswitchl as indicated at il?. in Figure 1,v so that each ttime the switch e3 is operated, the .rotatable member Il! is caused to move through a -pant of a revolution toA bring an empty saddle It!Y to the transfer station and simultaneously tocarryannisbed -pipe to the delivery station and .advance the 'pipesl in the intermediate saddles one. station in the .iinishing cycle.

The combinationof press, transfer mechanism, and .finishing machine enables a shaped pipe to be Withdrawn: from the mould and made ready for'drying, without manual aid. Use of the fringe as a'detectorensures that .only when a mould has been lled-whatever the variation in time taken to fili the mouldcan a pipe be extruded from the mould, and the remaining operations follow .in thev desired sequence under the control of mechanisms directly :actuated by the fringe or of other meclianismsset in operation by such actuation;

I claim:

1.. Method of producing pipes, conduits, or like articles from clay, comprising extruding a mass of clay into amould4 chamber the base of which is closed by a movable table for the time being locked against the end of said chamber, causing a fringe `ofclay'to exude from one or more aperturesformed between the base of said chamber and the adjacent face of the table as evidence of the-completion of a moulding operation in said chamber, and causing said fringe to eiiect release of said table, thus allowing the moulded article to be extruded from the mould Without manual control.

2. Method according to claim 1, comprising moving the table by the force of extrusion, causingthe table to eiect stoppage of the extrusion ofthe clay and thus the movement of the table after a pre-determined length of article has been extruded, returning the table to its initial position inA engagement with mould, and causing the table to eiectfrecemmencement of the extrusion of th'efclay astheftalefap'proachesitszlinitial position;

`3. Methodiccondingtovclaim 1, comprising moving theitablebeyundzthealnnit Zof its 'extrusion movement :and `,utilizing/:such Aadditional .movement to causeiactuation 'ofea transfer'mecliansm for removing thearticlesfrom the table` as they are completed, andfcausirig: the table to'dwell in its lower-most 'positionduring the transferring operation.

ifi. Method'of producngpipesyconduits, or like articles from: clay,. comprising lcictruding a .mass of clay intofalmouldichamber'tlfe base of which is closed vby a movable table .-for the time 'being locked against thefendI bifsaidf'ch'amber, causing 'a fringefofrclay to eexude: from ton'eormore apertures formed between the base of said 'chamber and `theladjacent facefof thertabl'e as evidence of `the completicrr'of.:a moulding, operation in said chamber, 1causingstddrfringe to 'effect release 4of said table, moving; the tableby theflforce -of extrusion, ycausingvthe table to=eect stoppage of the extrusionfcf theclay-'and thus the movement 4of the table after alipredetermined length 'of article has Ibeen extruded, lmov-i'ng the table beyond the limi-t -ot :its extrusion--movemen't and utilizing suclr additionalrmovement to 'cause 'actuation of a transfer mechanism for removing the articles 'fromf `the-'table.toa .finishing mechanism as they are completed, rcausing 'the table to dwell in its -lowermost position during 'the transferring operatiomand causing'sa-idlfrmge to'f'eect actuation' of the nnish-lng-mechanism-so that it performs a -nishing operation 'on' @ne article 'during the 'extrusion off-the inextfsucceeding article and itsv transfer tol Ithe finishing .mechanism 5. Amoulrling press for Iforming pipes, conduits, or like articles fromfclayfcomprisinga moulding chamber, .a 'base member` imsaid -moulding chamber, a :mnvablelsupporting table; .means for locking said table-'against tnefend of said moulding chamberleaving anaperture-giving access to said mouldingfchambenmeans forextruding clay into said lmouldingwelaamber and allowing `a fringe of f clay to exude tmvoughsaid aperture as evidence of the completion of' almoulding operation, and means responsive to the'exudation of said fringe for releasing said. locking. means', 'thus allowing said. table- -to be movedI and themoulded article to be extruded-from the moulding chamber witnout manual con-troll.

6. Apparatusvaccording, to-claim -5, comprising a 'counterpoise to enable the table to -be lowered -by the forceof extrusion, mea-ns responsive to the movement of, tnetableffor stopping the extrusioni oi the-clay after a pre-#determined length of article has been extruded, a cutting device arranged-to passthroug-hthelextruded mass 4a-t the base of the moulding chamber vtol separate the completed article vfrom thefmass, means for returning said- `table to itslinitialposition engagement with the-mould, and means responsive to the movement of: Ithe table tor .recommencin'g extrusion asf the table-approaches its initial position.

7. Apparatus according -to 'claim 6, comprising means responsive. to: themovement of the table forv actuating; saidfcutting: device, as the table reaches the limit' ot itsextrusio'nmovement.

8. Apparatus according toclaim 7, comprising means forv moving the table beyondI the limit of its extrusion movementfscfas to'tmove the completed larticle clearA of the'baseofthe'mould for 'ge purpose.1 of. removing tire article 'from the ble.

9. Apparatus according to claim comprising a counterpoise to enable the table to be lowered by the force of extrusion, means responsive to the movement of the table for stopping the eX- truson of the clay after a pre-determined length of article has been extruded, and means for moving the table beyond the limit of its extrusion movement so as to move the completed article clear of the base of the moulding chamber for the purpose of removing the article from the table.

10. Apparatus according to claim 5, wherein the means for effecting release of said locking means comprises an electric switch disposed in the path of exudation of the fringe.

11. Apparatus according to claim 5, comprising an electric switch disposed in the path of eXudation of the fringe, pneumatically operated locking means, an air valve controlling such locking means, and a solenoid arranged to be operated by the fringe-controlled switch and upon such operation to actuate said valve to release said locking means.

12. Apparatus according to claim 11, wherein the solenoid is connected to a two-armed lever, one arm of which is connected to the air valve and the other arm constitutes a reversing lever arranged to be actuated by the table as it returns to its initial position so as to cause the locking device to become operative.

13. A moulding press for forming pipes, conduits, or like articles from clay, comprising a moulding chamber, a base member in said moulding chamber, a freely movable supporting table arranged to be lowered by the force of extrusion, means for temporarily locking said table against the end of said moulding chamber leaving an aperture giving access to said moulding chamber, means for extruding clay into said moulding chamber and allowing a fringe of clay to exude through said aperture as evidence of the completion of a moulding operation, means responsive to the exudation of said fringe for releasing said locking means andV thus allowing said table to move and the moulded article to be extruded from the moulding chamber, means responsive to the extrusion movement of the table for stopping the extrusion of the clay and thus the movement of the table after a pre-determined length of article has been extruded, a cutting device arranged to pass through the extruded mass at the base of the moulding chamber to separate the completed article from the mass, a grabbing device for moving the table beyond the limit of its extrusion movement, and means responsive to the movement of the table under the action of the grabbing device for reversing the grabbing device as the table reaches the limit of such movement so as to cause the grabbing device to urge the table in the return direction.

14. Apparatus according to claim 13, wherein the table is counter-balanced and completes its return movement under its own momentum assisted by the locking action of the locking device.

15. Apparatus according to claim 14, comprising a shaft extending downwardly from said table and formed with a reduced portion terminating in a head, a grabbing device including a pair of hook members provided with pins, and a pair of stationary frames formed with cam slots in which said pins are arranged to bear so as to move Isaid hook members into and out of engagement with said head, said hook members being arranged to slide along the reduced portion of said shaft during the reverse movement of said grabbing device so as to cause a dwell of the table in its lowermost position.

16. Apparatus according to claim 15, wherein the locking device comprises toggle mechamsm.

17.'A moulding press for forming pipes, conduits, or like articles from clay, comprising a moulding chamber, at least one core in said moulding chamber, a base member in said moulding chamber, said base member being formed with an aperture co-operating with said core to form an extrusion throat, a movable die member, a movable supporting table formed with a core member co-operating with said die member, a locking devicefor urging said table towards said moulding chamber so as to lock said die member between the end of said moulding chamber and said table leaving an aperture giving access to said moulding chamber, means for extruding clay into said moulding chamber and allowing a fringe of clay to exude through said aperture as evidence of the completion of a moulding operation, and means responsive to the exudation of said fringe for releasing said locking device, thus allowing said table to move and extrusion of the article to continue through said extrusion throat.

18. Apparatus according to claim 5, comprising a transfer mechanism for removing the completed articles in succession from the table, and means responsive to the movement of the table as it approaches its lowermost position for actuating the transfer mechanism.

19. Apparatus according to claimv 18, comprising a finishing mechanism adapted to receive the articles in succession from the transfer mechanism, and by means responsive to the exudation of the fringe at the press to initiate operation of the finishing mechanism.

20. Method according to claim 1, comprising moving the table by the force of extrusion, causing the table to effect stoppage of the extrusion of the clay after a predetermined length of the article has been extruded, moving the table beyond the limit of its extrusion movement and utilizing such additional movement to cause actuation of a transfer mechanism for removing the articles from the table as they are Icompleted, causing the table to dwell in its lowermost position during the transfer operation, returning the table to its initial position in engagement with the mould, and causing the table to effect re-commencement of the extrusion of the clay as the table approaches its initial posiion.

JOI-IN 1'". BOOTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,651,203 Hibbins Nov. 29, 1927 1,875,738 Jones Sept. 6, 1932 2,282,282 I-Iamlen May 5, 1942 

